A CHARGING DEVICE AND HAND-HELD DEVICE FOR A SMALL MOBILE ELECTRICAL DEVICE

• US 20160134151A1
• Filed: 06/11/2014
• Published: 05/12/2016
• Est. Priority Date: 06/14/2013
• Status: Active Grant

• Current Assignee: Trisa Holding AG
• Original Assignee: Trisa Holding AG
• Inventors: FISCHER, Franz, MEIER, Hanspeter
• Granted Patent: US 10,116,172 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0032 disconnection of loads if battery is not under charge, e.g. in vehicle if engine is not running
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

A charging device having contactless transmission of electrical energy in order to supply energy to a wireless hand-held device. An electronic circuit for feeding an inductive energy transmitter is designed to adapt energy fed to the inductive energy transmitter in accordance with energy drawn from the inductive energy transmitter. A hand-held device is designed to interrupt the supply of a load when energy is fed into the hand-held device by means of the inductive energy transmitter.

Claims

1. A charging device for the contactless transmission of energy for the energy supply of a cordless hand-held device, wherein the charging device comprises an electronic circuit for feeding an inductive energy transmitter, and the circuit is configured to adapt energy fed to the inductive energy transmitter, in accordance with energy taken from the inductive energy transmitter.

2. A charging device according to claim 1, wherein the circuit comprises:

a primary winding for feeding a hand-held device, wherein the primary winding is part of an oscillation circuit,

a feed circuit for the pulsed feeding of energy into the oscillation circuit,

a detection winding which is magnetically coupled to the primary winding; and

a control circuit which rectifies the voltage at the detection winding, and interrupts or attenuates the pulsed feeding by the feed circuit when this voltage exceeds a threshold value,

and wherein optionally the feed circuit and the control circuit are constructed of discrete switching elements.

3. A charging device according to claim 2, wherein the control circuit comprises:

a rectifier circuit for forming a rectified voltage from the voltage at the detection winding, and an interrupter circuit which, when this rectified voltage exceeds a threshold value, suppresses or attenuates an activation of a switching element feeding the oscillation circuit.

4. A charging device according to claim 3, wherein the interrupter circuit intermittently suspends the suppression of the switching element feeding the oscillation circuit and by way of this maintains the oscillation of the oscillation circuit.

5. A charging device according to claim 3, wherein the interrupter circuit comprises a second switch which is arranged in a manner such that when the rectified voltage of the detection circuit exceeds a threshold value, it pulls down the potential at the base of the switching element feeding the oscillation circuit.

6. A charging device according to claim 1, wherein the circuit comprises:

a primary winding for feeding a hand-held device, wherein the primary winding is part of an oscillation circuit,

a driver circuit for the pulsed feeding of energy into the oscillation circuit in accordance with a driver signal,

a current measuring circuit for producing a current measurement signal corresponding to a current flowing into oscillation circuit,

a control device which is configured to detect the current measurement signal and, in accordance with the current measurement signal, to generate the driver signal for the activation of the driver circuit as a pulse-width modulated signal with a frequency corresponding to a resonance frequency of the oscillation circuit.

7. A charging device according to claim 6, wherein the control device is configured to be situated in a sleep state or in a charging state, in the sleep state to intermittently generate a driver signal during a test time period and thus to feed energy into the oscillation circuit, to test as to whether the current measurement signal thereby exceeds a first threshold value, and if this is the case, to change into the charging state, and if this is not the case, to remain in the sleep state.

8. A charging device according to claim 7, wherein the control device is configured, in the charging state, to essentially continuously generate the driver signal, to test whether the current measurement signal thereby falls short of a second threshold value, and to change into the sleep state if this is the case, and to remain in the charging state if this is not the case.

9. A charging device according to claim 6, wherein the current measuring circuit comprises a measuring shunt and a rectifier circuit for rectifying a voltage occurring across the measuring shunt and for generating the current measurement signal, and the control device is realised by a microprocessor or microcontroller, and optionally the microprocessor or microcontroller comprises an analog input for determining the current measurement signal.

10. A charging device according to claim 6, comprising a supply securing circuit which pulls the voltage at a connection point (Vp) to a reference voltage, wherein the connection point is connected to a communication lead of an interface to a supply device, and the charging device is designed to measure a voltage at the connection point and to modify a charging procedure by the charging device in accordance with the measured voltage.

11. A hand-held device with a contactless energy supply, comprising a secondary winding for the inductive energy transmission from a charging device to the hand-held device, an electrical energy store chargeable via the secondary winding, a consumer and a switching device for the switching on and off the supply of the consumer by the energy store, wherein the hand-held device comprises a protective circuit which interrupts the supply of the consumer when energy is fed into the hand-held device via the secondary winding.

12. A hand-held device according to claim 11, comprising a current measuring device which detects a charging current in a charging current circuit of the hand-held device, and the protective circuit interrupts the supply of the consumer when the charging current exceeds a threshold.

13. A hand-held device according to claim 12, wherein the current measuring device comprises a measuring rectifier which rectifies a voltage across a measuring element in the charging current circuit and forms a rectified voltage at a measuring capacitor, wherein the protective circuit interrupts the supply of the consumer when this rectified voltage exceeds a threshold.

14. A hand-held device according to claim 11, comprising a mechanical switch which pulls a control input of the switching device to a first potential, for switching on the supply of the consumer, wherein the protective circuit pulls the control input to a second potential given the occurrence of a charging current, and switches off the supply by way of this.

15. A hand-held device according to claim 11, comprising an integrated circuit with a measuring input, wherein the integrated circuit is configured to switch off the consumer should a voltage at the measuring input exceed a first threshold value.

16. A hand-held device according to claim 15, wherein the integrated circuit is designed to process the voltage at the measuring input as the battery voltage when it falls short of a second threshold value, and optionally to display a charging state of the electrical energy store to a user via display means in accordance with the battery voltage.

17. A hand-held device according to claim 16, comprising a battery voltage measuring resistor which pulls the voltage at the measuring capacitor to the battery voltage.

18. A hand-held device according to claim 11, with a contactless energy supply, comprising a secondary winding for the inductive energy transmission from a charging device to the hand-held device, and a battery which can be charged via the secondary winding, wherein the secondary winding is arranged on a hand-held device coil body, wherein the hand-held device coil body comprises a support section which is integrally formed as one piece, the support section is elastically deformable, and in the operationally ready state of the hand-held device, the hand-held device coil body with its support section presses against the battery and by way of this realises a resilient fixation of the battery.

19. A hand-held device according to claim 11, with a contactless energy supply, comprising:

a control unit a battery, a battery voltage measurement for measuring a battery voltage, a detection circuit for detecting as to whether the hand-held device is suppliable with energy by a charging part, and an isolating circuit, by which a charging of the battery can be interrupted, wherein the control device is configured,

in the case that the battery voltage has fallen short of a minimum value to carry out the charging of the battery during a defined minimum charging time, irrespective of the battery voltage.

20. A hand-held deice, according to claim 19, wherein the control unit is configured,

to reassume the charging of the battery, until the minimum charging time is reached, in the case that the charging of the battery is interrupted before reaching the minimum charging time, and the hand-held device is subsequently again suppliable with energy by the charging part.

21. A hand-held device, according to claim 19, wherein the control unit is configured,

after the minimum charging time has been reached and the hand-held device continues to be suppliable with energy by the charging part, to resume the charging of the battery, in the case that the battery voltage falls short of a lower threshold value.

22. A hand-held device according to claim 21, wherein the control unit is configured

to again interrupt the charging of the battery, in the case that the battery voltage exceeds an upper threshold value.

23. A method for charging an energy store of a small mobile electrical device with a contactless energy supply, wherein the small mobile electrical device comprises a control unit, a battery, a battery voltage measurement for measuring a battery voltage, a detection circuit for detecting as to whether the hand-held device is suppliable with energy by a charging part, and an isolating circuit, by which means a charging of the battery can be interrupted, and the method comprises the following step:

carrying out the charging of the battery during a defined minimum charging time irrespective of the battery voltage, in the case that the battery voltage has fallen short of a minimum value, for example by way of a minimum voltage for operation of the control unit having been fallen short of.